Hundreds of wildfires along the southern coast of Mexico create a thick cloud of smoke that hangs over the region. The location, widespread nature, and number of fires suggest that these fires were deliberately set to manage land, as does the time of year: in Mexico, the agricultural burning season usually occurs from March through May. Farmers often use fire to return nutrients to the soil and to clear the ground of unwanted plants. While fire helps enhance crops and grasses for pasture, the fires also produce smoke that degrades air quality.